Whether a healthy lifestyle can help support brain health and prevent Alzheimer's is a question that continues to intrigue researchers and fuel new investigations. There are no clear cut answers yet — partially due to the need for more large-scale studies — but promising research is under way. The Alzheimer's Association continues to fund studies exploring the influence of mental fitness, physical fitness, diet and environment. As the number of people affected by Alzheimer's rises, the effort to find prevention strategies continues to gain momentum.

Here are some things to keep in mind about the research underlying much of our current knowledge about possible prevention:

Insights about potentially modifiable risk factors apply to large population groups, not to individuals. Studies can show that factor X is associated with outcome Y, but cannot guarantee that any specific person will have that outcome. As a result, you can "do everything right" and still have a serious health problem or "do everything wrong" and live to be 100.

Much of our current evidence comes from large epidemiological studies such as the Honolulu-Asia Aging Study, the Nurses' Health Study, the Adult Changes in Thought Study and the Kungsholmen Project. These studies explore pre-existing behaviors and use statistical methods to relate those behaviors to health outcomes. This type of study can show an "association" between a factor and an outcome but cannot "prove" cause and effect. This is why we describe evidence based on these studies with such language as "suggests," "may show," "might protect" and "is associated with."

The gold standard for showing cause and effect is a clinical trial in which participants are randomly assigned to a prevention or risk management strategy or a control group. Researchers follow the two groups over time to see if their outcomes differ significantly.

It is unlikely that some prevention or risk management strategies will ever be tested in randomized trials for ethical or practical reasons. One example is exercise. Definitively testing the impact of exercise on Alzheimer's risk would require a huge trial enrolling thousands of people and following them for many years. The expense and logistics of such a trial would be prohibitive, and it would require some people to go without exercise, a known health benefit.

Prevention and risk management studies need healthy participants who are willing to make a long-term commitment to moving the field forward. You can find prevention trials currently recruiting through the Alzheimer's Association TrialMatch tool.